# Design lab for physics - rubber bands

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We were told to do a lab involving rubber bands and projectile motion in some sense. My group shot the rubber band and measured the distance moved as a function of its extension.

I graphed this and found that it seemed to be a linear relationship. Now, my question is if this is too simple to be DCP assessed? I don't really do any calculations, apart from the average and standard deviation, which is managed by Excel. We won't do many labs, so I want it bo be assessed. Anyone knows?

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So as far as I understand, you extended the rubber band by the same length of extention every time, right?

Well, it does seem fairly simple, maybe you should try throwing something forward with a rubber band. Haha, look what I found http://www.selfdefen...un-p-16746.html I find it hilarious! But what I mean is try extending the rubber band the same length every timd, hold in in a 'peace sign' position on one end, and on the other end have an item that you will be measuring how far it will get thrown.Mass will definitely have to be appropriate!

Well, I think that labs that are assessed are supposed to be a bit more complicated, this one seems to be fairly simple.. but I can't think of anything else to do with a rubber band that will create a projectile motion.

Or you can create something along these lines which is far more creative: http://teachingphysi...otion-activity/ In fact, I think its a great lab to do!

Edit:

the links didn't open for me when I tried to open them, so

I can't find it any longer after I closed it...

<h3 class="storytitle">Projectile Motion Activity</h3> Filed under: Activities, Physical Science — Scott @ 8:45 pm

Tags: projectile motion

I’ve been searching for a projectile motion activity/lab for my physical science class. I completely forgot about this one, and I’ve done it for years. We are going to make catapults from popsicle sticks, hot glue, rubber bands, and a spoon.

I like this lab because the hot glue allows for rapid build and repair, and there is a definite need for repair and modification in this project. The kids typically build the frame from the popsicle sticks and then try to attach the spoon with rubber bands. The spoon is the launcher for the catapult. Usually, they find there is no way to connect the rubber bands, so they start adding little posts. The next problem they encounter is the rubber bands aren’t tight enough so the object doesn’t launch very far. They then tighten the rubber bands and the frame starts to collapse. So they need to go back and reinforce the frame.

At this point one of three things happens.

1. The catapult is improved and they start launching marshmallows.
2. They realize they can rebuild the catapult rather quickly and so start all over and improve their design.
3. The catapult falls apart, they attempt improvements, but basically give up.

The picture isn’t a great example, but it is a starting point.

Edited by Peachez

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Perhaps it is a bit too simple for the processing part. Hmm. Maybe repeat it with different masses or thickness to see if the mass/thickness is independent of the velocity/distance?

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Well, the thing is that I already have my data, and I can't redo it. So what I was asking for was ideas about what more processing I could do.

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I do not think that there is much more to do in this lab because it looks fairly simple to me.

Calculations, graphs.. nothing less nothing more.

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I do not think that there is much more to do in this lab because it looks fairly simple to me.

Calculations, graphs.. nothing less nothing more.

Well, thank you anyway. At least I have D and CE assessed.

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No problem.

But hey, you will be assessed on more than one lab, so next time make sure that you do a more difficult one.. or at least one that you will know for sure you will be able to write a lot on.

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You could go the route of statistical analysis, adding variance and best-fit and chi squared test, if it fits, for fluff

Also, you could [if you haven't] calculate what you'd expect the distance to be as you pull the rubber band more, increasing tension. I don't know that it is possible to calculate the distance theoretically, but you could at least say it's directly proportional to how long you've pulled it. And if there is a manageable equation, do percent error.

Perhaps you can make a model/function for this rubber band. Or get Excel to make it for you.

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Just a suggestion: you could ask your teacher to make a lab that's only assessed for DCP. In our school we almost always assess the components separately and i think this makes it easier to get a good grade. For physics for example if your teacher gives you the lab outline, like something on spring constants and rubber bands and oscillations, where you have to find a single value for k by two different methods (extension and oscillation), then you can be assessed for DCP and get a fairly easy 6.

In terms of this particular lab, the experiment does seem a little simplistic. Maybe you could complicate things a little by adding variables and doing additional trials?

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yeah i really wish that was the case in my school.

The only problem is that I have an unorganised **** for a teacher, who doesn't even keep track of what labs we've done so far.

And he takes it upon himself to do 10 jobs at once, thus keeping his job as a physics teacher for the end.

SO basically, most of the labs we hand in have DCP and CE assessed and the ones with Design have all 3 criteria's assessed...its really crap...

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@tilia,

hey..we decided to do the exact same thing for the exact same lab.

Don't worry its not too simple as long as you have identified enough relevant variables.

Btw, our group kinda messed it up, so would it be ok if u sent me just the design portion of your lab??

thnx...

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@tilia,

hey..we decided to do the exact same thing for the exact same lab.

Don't worry its not too simple as long as you have identified enough relevant variables.

Btw, our group kinda messed it up, so would it be ok if u sent me just the design portion of your lab??

thnx...

Well, I think that would be approaching plagiarism.

For design labs, just state the variables (controlled, independent and dependent), explain how you'll keep the controlled ones constant, explain what you will be, how many trials you'll do and what values of the independent variables you'll use. That's pretty much it.

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